Regensburg 2013 – scientific programme

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DS: Fachverband Dünne Schichten

DS 23: Focus Session: Thin Film Photovoltaic Materials and Solar Cells II

DS 23.8: Talk

Wednesday, March 13, 2013, 16:45–17:00, H8

Diffusion of copper in In₂S₃ layers prepared by ion layer gas reaction method — •Albert Juma, Rodrigo Sáez-Araoz, Christian-Herbert Fischer, and Thomas Dittrich — Helmholtz-Centre-Berlin for Materials and Energy, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.

Diffusion of copper in semiconductors remains an important phenomenon in photovoltaics because it affects the electronic properties, formation of interfaces, solar cell characteristics and stability. In₂S₃ layers were prepared by ILGAR (ion layer gas reaction) method with InCl₃ and In In(OCCH₃CHOCCH₃)₃ as precursor salts to obtain Cl-containing and Cl-free layers, respectively. Diffusion experiments were performed by annealing Si/In₂S₃/CuSCN layer systems at different temperatures and times and then etching away CuSCN in pyridine solution. The concentration profiles of Cu in In₂S₃ were obtained using Rutherford backscattering spectrometry (RBS) from which the diffusion coefficients were determined as a function of temperature. The diffusion in Cl-containing layers was limited by a lower solubility limit while the Cl-free layers showed one diffusion process with a relatively higher solubility. The activation energies for Cu diffusion were 0.041eV and 0.24 eV for In₂S₃ layers with and without Cl respectively. The influence of In-Cl bond on the local structure of In₂S₃:Cl and on the diffusion process of Cu⁺ are discussed.